Conductive probe assembly and method of using

ABSTRACT

A conductive probe assembly useful in testing and, in modified form, in protecting a communications cable containing modular splice assemblies wherein each module is multiperforate to provide access to each inner contact element.

United States Patent Enright et a1.

CONDUCTIVE PROBE ASSEMBLY AND METHOD OF USING Inventors: Dennis J. Enright, St. Paul; Richard D. Kahabka, Burnsville; Donald F. Miller, St. Paul, all of Minn.

Minnesota Mining and Manufacturing Company, St. Paul, Minn.

Filed: Nov. 23, 1970 App]v No.: 91,780

Assignee:

Related US. Application Data Division of Ser. No. 823,598, May 12, 1969, abandoned.

US. Cl. ..339/108 TP, 324/72.5 Int. Cl. ..H0lr 11/18 Field of Search ..339/96, 108, 111; 324/725,

[ 1 Oct. 17, 1972 [56] References Cited UNITED STATES PATENTS 3,447,078 5/1969 Levy ..339/108 TP 3,474,386 10/1969 Link ..339/1ll 2,425,802 8/1947 Harris et a1. ..339/1 08 TP 2,663,844 12/1953 Earle et a1 ..339/l08 TP 2,922,954 l/l960 Bigelow ..324/72.5

FOREIGN PATENTS OR APPLlCATlONS 30,313 3/1911 Great Britain ..339/1()8 '1'? Primary Examiner-J0seph H. McGlynn Att0meyKinney, Alexander, Sell, Steldt and Delahunt [57] ABSTRACT A conductive probe assembly useful in testing and, in modified form, in protecting a communications cable containing modular splice assemblies wherein each module is multiperforate to provide access to each inner contact element.

1 Claim, 8 Drawing Figures CONDUCTIVE PROBE ASSEMBLY AND METHOD OF USING This application is a division of copending application Ser. No. 823,598 filed May 12, 1969 and now abandoned.

This invention relates to the splicing of communications cables. There is provided means and method for making electrical connection between corresponding wire-ends of such cables in a simple, rapid and effective manner, with production of a neatly and compactly assembled, easily traced and tested splice assembly. Stripping of insulation and soldering of wire ends is avoided. Identity of wires and wire-pairs-is easily determined and maintained. A minimum of space is required. All loose wire-ends and connectors are eliminated.

More particularly, the present invention in one important aspect relates to improved means and methods for obtaining accessto any desired wire-pair or number of wire-pairs of a communications cable system. In a more specific aspect the invention relates to probeassemblies for making direct contact with some or all of such wire-pairs. In a related aspect the invention relates to probe assemblies for providing protection to such cable systems for disruptive high voltage surges.

The practice of the invention makes use of modular communications cable connectors as described and claimed in said application Ser. No. 823,598. Such connectors typically consist of elongate interfitting base, body and cover members. The body member carries a double row of contact elements, the elements being disposed alternately close to and distant from one edge; and the body is multiperforate along said edge, each perforation providing access to a corresponding element. Wire ends from a first cable bundle of wire-pairs are supported across the base and beneath the body, and wire-ends from the opposing cable bundle of wirepairs.are supported across the upper surface of the body and beneath the cover, with each wire in position for contacting an appropriate contact element; and the several members are then forcefully pressed together to complete the modular connection.

In the drawing,

- FIG. 1 is a representation of a typical module in closed condition,

FIGS. 2, 3, and 4 represent portions, partly in section, of representative forms of probe members for use with the completed module of FIG. 1,

FIG. 5 is a representation of a composite probe member having particular utility as a protective device,

FIG. 6 is a representation in cross-section of a portion of a completed module, 9

FIG. 7 is a representation of a portion of an inner surface of a module body member, and

FIG. 8 is a schematic illustration in perspective of a communications cable splice area partly cut away and using modular connectors of FIG. 1 disposed for easy application of probe members of FIGS. 2-5.

The module 31 of FIG. 1 is composed of base 33, body 34, and cover 35, the body being in two segments 36 and 37. Channels 41 in the base, and channels 59in the body, serve to receive wire-ends to be connected. Perforations 52 in the body provide access to the several contact elements. Identifying ridges 68 along the perforate edge identify the wire-pair positions.

The internal structure of the module assembly is indicated in FIGS. 6 and 7. A double-ended contact element 69 extends through slots 49 and 54 in the body 34 across opposing channels 41 and 59 and makes permanent spring compression reserve contact with wires 71 and 72 contained therein. The excess wire ends are severed by cutting blades 39 and removed. Access to the central portion of the contabt element is provided through perforations 52. To achieve compactness, contact elements 69 are disposed alternately along inner channel 50 and outer channel 511 of lower body segment 37, the perforations 52 therefore being alternately long and short as shown in FIG. 7.

A typical assembly of a plurality of connector modules in a completed fold baclk splice arrangement between two cable ends is illustrated in FIG. 8 wherein the splice assembly is indicated as being hermetically enclosed within a casing 87 sealed to the cable ends at end seals 88. The modules 31 are arranged longitudinally of the splice area and assembled circumferentially thereof and with the perforate edges facing outwardly. Such assembly makes possible the simplified testing of individual splices or groups of splices, simply by the application of suitable probes at the perforated module edges once the casing 87 has been opened.

The assembly also makes possible the protection of the cable from harmful surges of electricity.

The practice of the present invention will now be described inconnection with the devices illustrated in FIGS. 2-5.

FIGS. 2-4 illustrate a number of probe modifications which may be used with perforate connector modules.

The device of FIG. 2 consists of an elongate U- shaped insulating beam 81 supporting a longer probe 82 and a shorter probe 83. Compression springs 73, 74 make electrical contact between the movable probes and external fixed contacts 75, 76. As many additional pairs of probes as may be desired for a complete module may be included in a single beam 81; or a single pair may be used. The device permits making contact with adjacent contact elements within the module, through the external contacts 75, 76 and to meters, lamps, phones or other test devices as desired for testing of any particular wire-pair.

A second type of device 84 illustrated in FIG. 3 cmploys rigid probe elements 77, 78 rigidly mounted in a solid insulating bar 79. The elements are of slightly reduced length so as to remain just out of contact with the contact elements 69 when fully inserted in the perforations 52 of the body 34 and with the surface of the bar held tightly against the edge of the module. In the device 85 of FIG. 4 the probes may or may not be spring mounted, and each is provided with a short insulating tip 86 serving to define a fixed flashover distance between the grounded probe and the contact element. In both instances grounding of the probes provides a protective high voltage flashover capability within the module.

The assembly 89 of FIG. 5 illustrates a preferred form of protective device. The probes 90, 91 are mounted in a conductive strip 92 to one end of which is attached a ground wire 93 the other end of which may be connected to a suitable ground. The length of the strip is substantially equal to that of the body 34 and tions at a mating wire-pair location of an elongate communications cable connection module having alternately deep and shallow edge perforations for exposing adjacent contact elements, the lengths of said probes being just sufficiently less than the depth of the corresponding perforation to its contact element to provide a normally non-conductive protective spark discharge gap between said probe and said element, and including conductive means for grounding each said probe.

* 1F IF i 

1. A probe member comprising an elongate support carrying at least one long and one short electrically conductive pin probe element in closely adjacent parallel position fOr insertion into adjacent edge perforations at a mating wire-pair location of an elongate communications cable connection module having alternately deep and shallow edge perforations for exposing adjacent contact elements, the lengths of said probes being just sufficiently less than the depth of the corresponding perforation to its contact element to provide a normally non-conductive protective spark discharge gap between said probe and said element, and including conductive means for grounding each said probe. 